DeDRM not working on a new book released 10/24/25

[Freshenstein]

A book just came out yesterday and when I tried to use Jadehawk's method to get the Key, I got this error:

BookOpen error 14 Missing magic bytes
Invalid book format, maybe KF8/MOBI?

I was able to successfully strip the DRM from a couple other books at the same time. When I copied the file into calibre, instead of the normal .kfx format, it shows as .azw format so that may have something to do with it.

This is the book I was trying to strip the DRM from: https://www.amazon.com/Boat-Wizard-Fantasy-Adventure-Coastal-ebook/dp/B0FWRYP8NS/

I tried a few other, older methods that did not work either.

Any assistance would be appreciated. Thank you.

[Satsuoni]

As mentioned, running the extractor should produce both keyfile and **.k4i file, as long as you have KFX books in library (scanned folder). You should check if k4i (json file) has kindle.account.tokens and kindle.account.secrets entries filled. Then, you should import file in calibre by clicking on "Kindle for Mac/PC ebooks" and "import existing keyfiles" inside. Then drag book file to calibre as normal, and it should work... In theory. k4i generation was added specifically to deal with older format books in the first place. Please tell if it does not work. (And remember that it needs KFX books to be generated! That is where it gets secrets from)
Edit: looks like there might be a bug in k4i generation. I am not sure if I should fix it in extractor or dedrm itself.

[Freshenstein]

Yeah that was the problem. I must have mixed up the versions as I had both .14 and .15 zips downloaded. Works great now. Thanks for all the help!

[bhchan]

FWIW
I noticed that I needed to generate a new keyfile every time I download new books... so I added a KeyExtract.bat file in "My Kindle Content" along with the latest KFXKeyExtractor28.exe. It generates 'keyfile' and 'keyfile.k4i'
I point the 'ugly text' to that keyfile and (not sure if this helps) added the k4i into the Kindle 4 PC/MAC area.

then, after I download new books with K4PC, I go to the My Kindle Content folder, run the bat file, and then 'Add book' works without problems. This is with a colorsoft running the latest firmware.

Bat file contains one line:
"C:{ME}\OneDrive\Documents\My Kindle Content\KFXKeyExtractor28.exe" "C:{ME}\OneDrive\Documents\My Kindle Content" keyfile keyfile.k4i

Replace the two "C:{ME}\OneDrive\Documents" with where you have your "My Kindle Content" folder

[palbin24]

getting 0 byte keyfile and 1KB keyfile.k4i after following bhchan post
calibre-debug-log.txt

[ElleKayEm]

You're using Kindle for PC 2.8.0?

[bhchan]

Looking at your log, just want to make sure you did the following... hopefully this will help.
your bat file should say
"C:\Users\Peter\Documents\My Kindle Content\KFXKeyExtractor28.exe" "C:\Users\Peter\Documents\My Kindle Content" keyfile keyfile.k4i

the double-quotes are important because leftovers from MS-DOS days.

Also, I noticed lately, in Windows 11, I need to go to my kindle content folder and right-click 'open in terminal' and then run the bat from there. :( (But... I think your log file says you're running win10...)

Additionally, in the configuration for DeDRM, the 'ugly text box' it should say C:\Users\Peter\Documents\My Kindle Content\keyfile

[sychrobeep]

I'm having the same issue here – my entire library has converted (using the latest 10.0.15 release). The only book that has not converted is an AZW file. Here is my log:

calibre-debug-log.txt

[Satsuoni]

@sychrobeep, I have checked, and it looks like the pathways for KF7 is largerly the same. I did notice, however, that you don't have "Got DSN key from database" string in your debug log, which means that either your k4i file is invalid, or it is not set properly. Can you confirm that your k4i file contains "DSN" key and that it is properly imported in "Kindle for Mac/PC ebooks"? I remember when my import did not stick for some reason...

[sychrobeep]

The key starts {"DSN":" Followed by an long string of numbers.

I'm not that clear on what any of that means though.

I deleted and re-installed/re-ran everything and still had the same issue.

[Satsuoni]

The key starts {"DSN":" Followed by an long string of numbers.

That seems correct...

I deleted and re-installed/re-ran everything and still had the same issue.

Does your "Kindle for mac and pc keys" show the name of k4i file, like so?

[sychrobeep]

The key starts {"DSN":" Followed by an long string of numbers.

That seems correct...

I deleted and re-installed/re-ran everything and still had the same issue.

Does your "Kindle for mac and pc keys" show the name of k4i file, like so?

Ah I see what I missed - I added the path to the keyfile in the previous dialogue, but I didn't import the k4i into the k4pc box. I've just done it now and the book converted.

Thank you so much! :)

[Satsuoni]

Keyfile for KFX, k4i for older formats... You should not need to replace k4i until new version of K4PC (or if you log out and back in), but keyfile has to be refreshed for each (KFX) book. (Though you don't need to re-point it if you keep overwriting the same file)

[palbin24]

YesPeter AlbinOn Nov 11, 2025, at 7:35 PM, ElleKayEm ***@***.***> wrote: You're using Kindle for PC 2.8.0? —Reply to this email directly, view it on GitHub, or unsubscribe.You are receiving this because you commented.Message ID: ***@***.***>

[palbin24]

Let me know how I can help PeterOn Nov 11, 2025, at 7:35 PM, ElleKayEm ***@***.***> wrote: You're using Kindle for PC 2.8.0? —Reply to this email directly, view it on GitHub, or unsubscribe.You are receiving this because you commented.Message ID: ***@***.***>

[ElleKayEm]

I don't know why you wouldn't get any keys. Hopefully someone else has an idea.

[palbin24]

Thanks for checking The answer is probably in the log somewhere but it’s TMI and I get lost looking through it.PeterOn Nov 11, 2025, at 7:47 PM, ElleKayEm ***@***.***> wrote: I don't know why you wouldn't get any keys. Hopefully someone else has an idea. —Reply to this email directly, view it on GitHub, or unsubscribe.You are receiving this because you commented.Message ID: ***@***.***>

[palbin24]

Thanks for getting back to me I will respond tomorrow PeterOn Nov 11, 2025, at 9:45 PM, bhchan ***@***.***> wrote: Looking at your log, just want to make sure you did the following... hopefully this will help. your bat file should say "C:\Users\Peter\Documents\My Kindle Content\KFXKeyExtractor28.exe" "C:\Users\Peter\Documents\My Kindle Content" keyfile keyfile.4i the double-quotes are important because leftovers from MS-DOS days. Also, I noticed lately, in Windows 11, I need to go to my kindle content folder and right-click 'open in terminal' and then run the bat from there. :( (But... I think your log file says you're running win10...) Additionally, in the configuration for DeDRM, the 'ugly text box' it should say C:\Users\Peter\Documents\My Kindle Content\keyfile —Reply to this email directly, view it on GitHub, or unsubscribe.You are receiving this because you commented.Message ID: ***@***.***>

[palbin24]

DeDRM not working after successfully working after last issue. Calibre log attached.
calibre-debug-log.txt

[ElleKayEm]

Looks like KFX Input can't find the DRM voucher. Did you move the main book file out of its original folder structure?

[Freshenstein]

Got a new book that DeDRM is not working on: https://www.amazon.com/gp/product/B0DPRDDK1R

When I run KFXKeyExtractor28.exe "C:\\Users\\<username>\\Documents\\My Kindle Content" keyfile kindle_account.k4i, it does not generate a keyfile and all it says is

Scanning C:\\Users\\<username>\\Documents\\My Kindle Content for book folders
adding search dir C:\Users\<username>\AppData\Local\Amazon\Kindle\application
Kindle Directory: C:\Users\<username>\AppData\Local\Amazon\Kindle\application\Kindle.exe
Found sought after function
Got offset: 2a90000

I've had no issues with any other books.

[Satsuoni]

What happens if you run it on only that book in separate folder? Full output (sanitized)? And to confirm, B0DPRDDK1R_EBOK is the book in question, right?
Edit: and, since it seems to be in Indian store for me: does it open on Kindle for PC itself normally?

[Freshenstein]

What happens if you run it on only that book in separate folder? Full output (sanitized)? And to confirm, B0DPRDDK1R_EBOK is the book in question, right? Edit: and, since it seems to be in Indian store for me: does it open on Kindle for PC itself normally?

B0DPRDDK1R_EBOK is the book in question, correct.

The book loads just fine in Kindle for PC and looks totally normal.

This is the entire screen I got. Only edited the username, the DRM key, and the DSN/Tokens entry. Only things in the directory I used was the B0DPRDDK1R_EBOK folder and KFXExtractor28.exe

PS C:\Users\<username>\Documents\My Kindle Content\New folder> .\KFXKeyExtractor28.exe "C:\\Users\\<username>\\Documents\\My Kindle Content" keyfile kindle_account.k4i
Scanning C:\\Users\\<username>\\Documents\\My Kindle Content for book folders
adding search dir C:\Users\<username>\AppData\Local\Amazon\Kindle\application
Kindle Directory: C:\Users\<username>\AppData\Local\Amazon\Kindle\application\Kindle.exe
Found sought after function
Got offset: 2880000
QObject::startTimer: Timers can only be used with threads started with QThread
DSN <data>
Tokens <data>
Fontconfig error: Cannot load default config file
Trying to open  B0DPRDDK1R_EBOK
amzn1.drm-key.v1.<data>$secret_key:<data>
PS C:\Users\<username>\Documents\My Kindle Content\New folder>

[Satsuoni]

Ok, I tried to get it... And yep, it sure crashes. I will investigate. That said, adding key line to keyfile allowed me to decrypt it fine. Tell me, does your key end with cc89? And key id with f88d?

[Freshenstein]

Ok, I tried to get it... And yep, it sure crashes. I will investigate. That said, adding key line to keyfile allowed me to decrypt it fine. Tell me, does your key end with cc89? And key id with f88d?

Yes my key does end with cc89 and key id ends with f88d.

I tried adding the key line directly to the keyfile and that did allow Calibre to convert it properly. I swear I tried that before but I must not have copied it correctly or something.

Thanks for all your help!

[Satsuoni]

I think I know what is wrong, kinda. I don't think it is worth doing a separate release for, since it is so rare... Do you know what the line in Calibre under languages is?

...
Ok, not what I thought at all, but still.
Here is a hotfix if you want it:
KFXKeyExtractor28_hotfix251210.zip

Edit: I messed with code randomly since last release, so I am not sure what I did to it. It seems to function still, but be aware that it might perform worse or output different things.

[palbin24]

I'm not sure what you are asking, but this is the directory where the book resides C:\Users\<user>\Documents\My Kindle Content

…

On 12/9/2025 4:44 PM, Satsuoni wrote: What happens if you run it on only that book in separate folder? Full output (sanitized)? And to confirm, B0DPRDDK1R_EBOK /is/ the book in question, right? — Reply to this email directly, view it on GitHub <#35 (reply in thread)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/B2BJ3KZAAR3OLL7FRYGCC2D4A47FDAVCNFSM6AAAAACKGMW2FSVHI2DSMVQWIX3LMV43URDJONRXK43TNFXW4Q3PNVWWK3TUHMYTKMRRGMYTENY>. You are receiving this because you commented.Message ID: ***@***.***>

[palbin24]

It's back again ... I copied the .kinf2024 file to C:\Users\Admin\AppData\Local\Amazon\Kindle\storage.kinf2024 as I was getting kinf not found error
calibre-debug-log.txt

[palbin24]

OK, false alarm? I reverted back to the original KFXKeyExtractor28.exe (not the hotfix) and it worked!?

[palbin24]

calibre-debug-log.txt
I have tried with both versions of the tool and neither seems to work.

[Satsuoni]

What is the output of KFXKeyExtractor28.exe?

[palbin24]

Something strange ... I reran with the hotfix and the process worked.

[hpcolus]

calibre-debug-log.txt
I get the same error.
I have kindle for pc 2.8
I run the keyextractor28 and in calibre dedrm imported the keyfile kindle_account.k4i
BTW i also tried the bat file key_finder.bat and is stuck waiting for calibre to be closed even if calibre is closed.
What step am i missing?

Output of keyextractor

adding search dir C:\Users\xxx\AppData\Local\Amazon\Kindle\application Kindle Directory: C:\Users\xxx\AppData\Local\Amazon\Kindle\application\Kindle.exe Memset 6E08EDE0 Found sought after function Found sought after function Got offset: 3150000 QObject::startTimer: Timers can only be used with threads started with QThread DSN r970Stnb657Jt07xrvndnAnfn0rhPPrG6UtA5266 Tokens 5mgdDWgTqrmAaysHz+nhZg7H7+5YS71v5P3Ow62r9tP+wEdCvRTNiWOtQdl27/7wYRZokpcOer0vgYknStiWfQ==,JwjmBYXpI8UOzgA2Q/Yb1Udw81HAohgg9z2PXsgktG4mc0iqxHp0HIlpFaEuq0dE79JH848yx5XhHz1VJ3UPCg== Fontconfig error: Cannot load default config file Trying to open B00T3H6KV4_EBOK amzn1.drm-key.v1.667006a0-0d43-4a20-b01e-042da5fc94e3$secret_key:3992f6916e768e7206a050305747cc65 Succesfully opened book C:\\Users\\xxx\\Documents\\My Kindle Content\B00T3H6KV4_EBOK\B00T3H6KV4_EBOK.azw This book does not use account secrets Trying to open B079RLR2KK_EBOK BookOpen error 31 DRM voucher decryption failed due to incorrect lock parameters amzn1.drm-key.v1.6acb64bb-41cd-409d-a7c6-e8b88bce5fba$secret_key:7c0c2e3f9ed3fbe2dbb685fd66e4f45d Succesfully opened book C:\\Users\\xxx\\Documents\\My Kindle Content\B079RLR2KK_EBOK\B079RLR2KK_EBOK.azw This book does not use account secrets Trying to open B0CGF9WDNT_EBOK amzn1.drm-key.v1.0a46514e-3bc4-40cc-bd7a-d1ad741ff60d$secret_key:22d00fc7ae83c31f6dff6eee2a0af169 Succesfully opened book C:\\Users\\xxx\\Documents\\My Kindle Content\B0CGF9WDNT_EBOK\B0CGF9WDNT_EBOK.azw This book does not use account secrets Trying to open NoteDocuments "device_serial_number":"xxxxxxxxxxxxxxxAnfn0rhPPrG6UtA5266" Writing DSN and secrets into kindle_account.k4i

[Satsuoni]

It literally printed three keys in your listing... Did you set the keyfile in the ugly textbox and the secrets k4i file in the Kindle for Mac/PC ebooks?

[hpcolus]

Here is the new log.
I was able to convert two books but one. I was able to run the key_finder.bat when I run the scrip inside "my kindle content" folder which previously I did run from another folder. The key_finder.bat generated an dedrm entry in kindle for pc

Can you explain this: Did you set the keyfile in the ugly textbox?

calibre-debug-log.txt

[Satsuoni]

It is where kindlekey.txt is on your picture. It seems set. Does the kindlekey.txt have all three entries? This one in particular: amzn1.drm-key.v1.6acb64bb-41cd-409d-a7c6-e8b88bce5fba$secret_key:7c0c2e3f9ed3fbe2dbb685fd66e4f45d

[hpcolus]

Problem solved. I reinstalled the DeDRM plugin but using the pre-release version 16. Now all books convert. Thanks.